1. Field of the Invention
The invention relates to an energy management system, and more particularly, to an energy management system for a case where a target value of a power consumption is set.
2. Description of Related Art
In some cases, a power company or the like that supplies power to a building sets a target value of a power consumption of the building. In this case, when the power consumption is controlled to or below the target value, a merit of enabling a reduction in electricity rate or the like is obtained.
In this context, there is disclosed in Japanese Patent Application Publication No. 2006-158146 (JP-A-2006-158146) a power supply management system that maintains a contract type so that a demand does not exceed a contracted level, and makes it possible to offer various services through effective utilization of a system to contribute to an increase in asset values of a complex housing.
Further, there is disclosed in Japanese Patent Application Publication No. 2001-008380 (JP-A-2001-008380) an art of leveling a power demand and ensuring an on-vehicle battery of a predetermined power to make it possible to cope with urgent outing as well in a system capable of transferring power between an electric vehicle and a residence reciprocally.
However, in the art described in Japanese Patent Application Publication No. 2006-158146 (JP-A-2006-158146), although power storage based on midnight power is disclosed, there is a problem in that no sufficient measure is taken to cope with a case where an actual power consumption is smaller than a target value.
Further, in the art disclosed in Japanese Patent Application Publication No. 2001-008380 (JP-A-2001-008380), only the on-vehicle battery is used. As a matter of course, therefore, the power demand can be leveled only when the vehicle is parked close to a building. Further, when inhabitants of the building is away from home in their vehicles, the power consumption is smaller and hence the surplus power tends to be larger than when the inhabitants are at home. That is, from the standpoint of power leveling, the storage of surplus power is desired precisely when the inhabitants are away from home.
As described hitherto, in the related art, there is a problem in that energy management is carried out inefficiently in a building in which a target value of a power consumption is set.